Abstract:We build a new time-difference model for velocity estimation based on the existing time-differenced carrier phase technique. In the new model, time-differenced pseudorange observations are included. The static and kinematic data of Beidou navigation satellite system (BDS) is used to verify and analyze the improved method. The results show that the precision of the new time-differenced method could reach mm/s level in static conditions, equal to the GPS precision, and the accuracy of horizontal is better than the vertical. Furthermore, while in dynamic conditions, the mean square statistics of the velocity discrepancies between BDS time-differenced method and IE (inertial explorer) accord with cm/s, and the accuracy of the horizontal is better than the vertical.